The moment Li Ping and her mob broke past a security guard, she knew she had passed the point of no return. It was 9.30am on a crisp, sun-drenched, day in October and the Beijing Number Six hospital's administrative building was lightly guarded. Her entourage of friends and relatives – most of them belligerent, track-suited men – charged into its fluorescent-lit hallways, banging on doors and accosting terrified nurses.

Li, a 34-year-old new mother, was struggling to prove a complicated case of medical malpractice involving a caesarean section, an intrauterine device and a tumour. Undoing a doctor's mistakes, she said, had cost her £3,000 – most of it borrowed – and ruined nearly a year of her life.

The hospital had shrugged her off repeatedly. Li did not consider herself a violent person, but she was firm in her resolve. Bringing an angry mob she knew was a high-stakes gamble – either she would get her compensation, or someone would get hurt.

China's healthcare system is plagued with violence and many of its tragic stories begin like Li's, with a negligent hospital administration or expensive procedure gone awry. Last year, seven hospital employees were killed and 28 injured across the country, most of them by dissatisfied patients or their relatives.

According to the China Hospital Management Association, patient-doctor disputes have risen 23% a year on average since 2002. A typical hospital suffers one attack every two weeks.

"It's not like there's one single thing that makes trust disintegrate between physicians and patients," said an American doctor who has spent years studying the issue.

GPs are scarce, as specialist work is more lucrative, so most patients are unable to build long-term relationships with their doctors. Treatment is expensive, waits are long, practitioners are underpaid, and many take bribes to stay afloat. Because medical treatment can easily wipe out a patient's life savings, emotions run high when things go wrong.

At Beijing Number Six hospital, Li led her supporters to a second-floor office, looking for her doctor. "He'll be here," she said. But after forcing their way in, they found only a group of lab-coated nurses hunched over paper-strewn desks. The doctors had left early, one said. Security had tipped them off.

The men began to point and yell, and Li collapsed into a chair, sobbing. "In the middle of the night, my son would cry mama," she said. "Every time I was in the hospital and he came to see me, he would cry. And then I would cry too." She looked up at the nurses. "You're all women. Some of you must be mothers. You must know what that's like."

The hospital treated Li with well-rehearsed tact. First, the nurses took her to a Communist party office down the hall, where she and her party were handed green tea. Forty minutes later a man led the group to a cramped "dispute resolution office" behind a corrugated door in the hospital courtyard. There a soft-spoken, grey-haired, woman in a lab coat sat Li down and, ignoring the glowering mob, invited her to recite her grievances.

"The reason you see this level of violence is that it works," said Ben Liebman, a professor at Columbia Law School, who has studied dispute resolution in Chinese hospitals. Hospitals were more concerned with avoiding violence than with due process; sometimes they overcompensated patients to pre-empt further protests. "They're incentivised to engage in a level of responsiveness, which in turn incentivises people to engage in a level of unrest," he said.

The staff member brought Li's case to the hospital's Communist party chief. A few weeks later she was granted £6,000 in compensation.

Officials have begun to address the issue of hospital violence, albeit with a heavy-handed twist. In October, the national health and family planning commission released security guidelines for hospitals, mandating that they installed alarm buttons, security doors and weapon-detecting scanners, as well as lay on one security guard for every 20 patient beds. Some hospitals are now teaching their doctors self-defence.

Experts have responded with scepticism. "If you have security forces stationed at a hospital, the message that you're sending is not one of safety, it's one of not being safe," said one foreign doctor.

The healthcare system in China has improved significantly over the years as the government pours billions of pounds of subsidies into reform. At present, 99% of the rural population gets some kind of insurance, up from 21% a decade ago.

Yet changes have been too slow, and often superficial, said a paediatric cardiologist at a prestigious Beijing hospital. She said she earns about £1,000 a month – slightly more than her housekeeper – for performing three to four surgeries a day. Her patients' families pay up to £5,000 for each operation, most of which is frittered away by hospital administrators. They assume the worst, and treat her terribly.